Their fame will go on and on! Heidi and Spencer Pratt indulge in Titanic PDA

KING OF THE CELEB WORLD: The couple did their best Kate and Leo impression [SPLASH]

The couple have gone from CBB runner-ups and legendary housemates to a footnote in a new housemate's personal history in the space of a day.

The Hills star Spencer is the brother of Stephanie, who entered the house last night – but instead of giving his baby sister the limelight, he chose to put on a PDA-riffic display with his surgically-enhanced missus.

As you do.

While Stephanie was being bundled into a house with White Dee and David McIntosh, Speidi rented a boat in Hawaii for some alone time.

Pfft, who are we kidding – they invited the paps along to flaunt their five-year marriage.

Dressed in a gold fish-scale bikini, Heidi showed off her washboard stomach and pert assets as she flung her arms around her reality TV husband.

But if their smooches and over-the-top embraces weren't enough to convince you of their love, Heidi and Spencer had a trick up their non-existent sleeves – to impersonate one of the most iconic couples of all time.

Who? Rose and Jack from Titanic, of course.

The peroxide blondes acted out the famous "I'm flying, Jack" scene from the tearjerker, and the resemblance was uncanny – well, if Kate Winslet and Leonardo DiCaprio were dressed in microscopic swimwear, that is.

After channelling the spirit of Hollywood blockbusters, Speidi then went for a snorkel while holding hands.

Er, we say snorkel, we actually mean they waded in the sea wearing snorkelling masks. But that's the same thing, right?

REALITY TV ROYAL FAMILY: Stephanie has followed in her brother's footsteps [FAMEFLYNET]